Utility companies (e.g., electrical, gas, and water utilities) are chartered with delivering a high quality of service to their customers. For example, in the case of an electrical utility, quality of power can refer to power delivered within a certain voltage range. In addition, it can refer to the number of interruptions and transient disturbances that take place over a given time period, which are ideally minimized. In some areas, local codes or ordinances mandate the quality of the power supply.
Some of the factors that may affect the quality of power delivered to customers include local voltage reductions and noise from switching circuits. In addition, defective or worn equipment can also cause problems, along with tree limbs growing through power lines and countless other power line disturbances. Problems with power line quality can lead to customer complaints and, in some cases the customer can lose all service (e.g., during failure of a defective transformer).
Typically, electric utility, companies use a grid of power lines and control transformers in an attempt to achieve a high quality supply of power. Utility companies may also measure power quality at major substations. However, attempts to solve monitoring quality at a high level are often not effective because loss of power and poor power quality is typically a local phenomenon that usually only affects a small number of customers connected to a local feeder line.
In some cases, lower level monitoring (e.g., at the neighborhood level) is done on a case-by-case basis. However, local monitoring on an ongoing and distributed basis may be considered not feasible because of the high cost involved in implementing an infrastructure for performing such monitoring.
In the drawings, the same reference numbers identify identical or substantially similar elements or acts. To easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the figure number in which that element is first introduced (e.g., element 204 is first introduced and discussed with respect to FIG. 2).